Ohhh...the weakness in making such a case about Paul is that Paul was fairly talkative, and no doubt would have mentioned in direct encounter with Jesus or direct witnessing of any sermon, miracle, moment, etc.
So, it would have been peripheral or with only one or two degrees of separation.
Paul’s Gospel was by revelation, not ancient oral tales, and established upon Scriptural substantiation, not the premise of assured veracity.
“Am I not an apostle? am I not free? have I not seen Jesus Christ our Lord? are not ye my work in the Lord?” (1 Corinthians 9:1)
“As we said before, so say I now again, If any man preach any other gospel unto you than that ye have received, let him be accursed.” (Galatians 1:9)
“But I certify you, brethren, that the gospel which was preached of me is not after man. For I neither received it of man, neither was I taught it, but by the revelation of Jesus Christ.” (Galatians 1:11-12)
“But when it pleased God, who separated me from my mother’s womb, and called me by his grace, To reveal his Son in me, that I might preach him among the heathen; immediately I conferred not with flesh and blood: Neither went I up to Jerusalem to them which were apostles before me; but I went into Arabia, and returned again unto Damascus.” (Galatians 1:15-17)